Salmon may face greater threat than water shortage

WILDLIFE

Glen Martin, Special to The Chronicle

Published
4:00 am PDT, Monday, July 25, 2011

A commercial fisherman who declined to give his name said he hasn't been able to prepare his boat for salmon fishing yet. The commerical salmon fishing season is set to open Sunday, May 1, 2011, the first full season since 2007. less

A commercial fisherman who declined to give his name said he hasn't been able to prepare his boat for salmon fishing yet. The commerical salmon fishing season is set to open Sunday, May 1, 2011, the first full ... more

Photo: Anna Vignet, The Chronicle

Photo: Anna Vignet, The Chronicle

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A commercial fisherman who declined to give his name said he hasn't been able to prepare his boat for salmon fishing yet. The commerical salmon fishing season is set to open Sunday, May 1, 2011, the first full season since 2007. less

A commercial fisherman who declined to give his name said he hasn't been able to prepare his boat for salmon fishing yet. The commerical salmon fishing season is set to open Sunday, May 1, 2011, the first full ... more

Photo: Anna Vignet, The Chronicle

Salmon may face greater threat than water shortage

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California's salmon wars have been characterized as a choice between thriving fisheries or prosperous San Joaquin Valley farms; there is not enough water, it has been argued, for both. But evidence is growing that the disposition of the state's scant fresh water supply may not be the biggest issue facing salmon.

Human population growth and climate change could be the ultimate factors determining the fate of the state's salmon, and both are far harder to address than water allocations.

It is becoming increasingly clear that sustained robust salmon runs and large human populations are incompatible, said Robert Lackey, a fisheries professor at Oregon State University and the lead researcher of Salmon 2100, a seminal investigation of future U.S. salmon prospects.

"In Europe and northern Asia, salmon numbers are inverse to human numbers," said Lackey. "As the human population went up, salmon went down and stayed down. The same thing happened in the eastern United States, and it's happening" in California and the Pacific Northwest.

Human impact

The reasons for the trend are not complicated. People inexorably exploit the precise resources salmon need for survival, observed Lackey: clean water and the timber that cools and stabilizes productive salmon-supporting watersheds. Urban development also takes significant - and generally, permanent - tolls on the runs.

Certainly, California's primary salmon-producing river - the Sacramento - is barely fulfilling its fisheries habitat functions. Lackey noted that much of the river's water is diverted south, and it has been dammed and extensively channelized, greatly reducing spawning zones and the cool, shaded niches young salmon need for rest and foraging. The state's second major salmon river, the Klamath, has also suffered major degradation.

True, the first years of the new millennium saw hundreds of thousands of chinook salmon return to the state's rivers to spawn. From 2000 to 2005, average annual catches in California and Oregon averaged 800,000 salmon, many of those fish originating in the Sacramento and Klamath watersheds.

"But those were years with especially abundant snowpack, so more fresh water went through the systems," Lackey said. "We can't rely on heavy snowpack year after year, especially given likely climate change scenarios."

Plus, said Peter Moyle, a professor of fisheries biology at UC Davis, most of those returning salmon were hatchery fish - and hatchery fish are not truly wild.

Trivial by comparison

It must be remembered, added Lackey, that the annual salmon yield of the Sacramento and Klamath drainages was once in the millions; from that perspective, the "big" runs of 2000-05 look paltry. And the years from 2006 to 2010 were marked by catastrophically low salmon returns: The fisheries essentially collapsed.

This fact is not lost on some of the biggest players in the salmon conservation game. Palo Alto's Gordon and Betty Moore Foundation, the nation's largest environmental philanthropic fund, has launched a multimillion dollar effort to save wild salmon - but not in California or Oregon. Rather, Moore's Wild Salmon Ecosystems Initiative is focused on preserving salmon populations and salmon-supporting watersheds in a great arc running from British Columbia north to Alaska and south along Russia's Kamchatka Peninsula.

The rationale for this strategy is simple, said the foundation's Michael Larsen: That's where the truly wild salmon, the salmon that have never so much as sniffed at a hatchery facility, remain in abundance.

"You look across the North Pacific and wild salmon are doing extremely well," Larsen said. "In fact, the productivity is the best we've seen since the 1970s."

Ideal conditions

Larsen explained that a great deal of resilience is built into the North Pacific's salmon populations: pristine watersheds, cold marine waters teeming with forage fish and broad genetic diversity in the five extant species of Pacific salmon. Some fisheries advocates are worried that the Moore Foundation's approach amounts to a kind of brutal triage - preserving the salmon of the North Pacific while abandoning the struggling runs in the Lower 48 states.

"I understand what Moore is doing, but it worries me that they are ignoring the huge watersheds (of the continental United States) that were once great salmon producers and could be again if they were properly restored and managed," said Zeke Grader, the executive director of the Pacific Coast Federation of Fishermen's Associations. "I don't mean just the Klamath and the Sacramento - I also mean the Columbia and the Fraser (in southern British Columbia). We need to save all the existing salmon habitat - including California's."

But Larsen said it's not a matter of writing off California's salmon.

"We're not advocating walking away from the Lower 48," he said. But "we feel we can get the most bang for our buck in the North Pacific."

Changing climate

While climate change will likely exert malign effects on southern salmon runs, they could also provide some opportunities for salmon in areas where they don't currently exist. Chinook salmon, in fact, are now showing up in northern rivers that were once too cold for them.

"Chinook have been reported in the McKenzie River" which drains into the Beaufort Sea near the Arctic Circle, said Lackey. "It's fascinating. In the future, we could well be managing Arctic salmon runs."

Even with a warming climate, it's unlikely California's salmon will go extinct - but their populations could stabilize at levels that would preclude commercial fishing.

"There are some positive developments," said Moyle, the UC Davis biology professor. "Preservation efforts are under way for cold water refuges like Blue Creek on the Klamath and Battle Creek on the Sacramento. But the impediments to substantive recovery are significant. In the end, we may have small runs maintained by human effort and considerable expense."